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Clinical, genetic, and molecular characterization of hyperphosphatasia with mental retardation: a case report and literature review.
Abi Farraj, L, Khatoun, WD, Abou Chebel, N, Wakim, V, Dawali, K, Ghassibe-Sabbagh, M
Diagnostic pathology. 2019;(1):123
Abstract
BACKGROUND Hyperphosphatasia with mental retardation syndrome (HPMRS) is a recessive disorder characterized by high blood levels of alkaline phosphatase together with typical dysmorphic signs such as cleft palate, intellectual disability, cardiac abnormalities, and developmental delay. Genes involved in the glycosylphosphatidylinositol pathway and known to be mutated in HPMRS have never been characterized in the Lebanese population. CASE PRESENTATION Herein, we describe a pair of monozygotic twins presenting with severe intellectual disability, distinct facial dysmorphism, developmental delay, and increased alkaline phosphatase level. Two individuals underwent whole exome sequencing followed by Sanger sequencing to confirm the co-segregation of the mutation in the consanguineous family. A biallelic loss of function mutation in PGAP3 was detected. Both patients were homozygous for the c.203delC (p.C68LfsX88) mutation and the parents were carriers confirming the founder effect of the mutation. High ALP serum levels confirmed the molecular diagnosis. CONCLUSION Our findings have illustrated the genomic profile of PGAP3-related HPMRS which is essential for targeted molecular and genetic testing. Moreover, we found previously unreported clinical findings such as hypodontia and skin hyperpigmentation. These features, together with the novel mutation expand the phenotypic and genotypic spectrum of this rare recessive disorder.
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[Gene analysis and literature review of autosomal recessive polycystic kidney disease].
Zhang, JW, Wang, C, Wang, CY, Qiu, ZQ
Zhonghua er ke za zhi = Chinese journal of pediatrics. 2013;(9):684-7
Abstract
OBJECTIVE The purpose of this study was to investigate the clinical and genetic characteristics of autosomal recessive polycystic kidney disease. METHOD Targeted sequencing was used on a children who was accurately diagnosed as autosomal recessive polycystic kidney disease in Peking Union Medical College Hospital to analyze the major clinical manifestations of the disease. An analysis of the PKHD1 genes was made on the patient, and then verified by polymerase chain reaction (PCR). And the related literature was reviewed also. RESULT The patient was a boy, 2 years and 3 months old, and had abdominal distention for about one year. The abdominal ultrasound suggested diffuse liver lesions, mild intrahepatic bile duct dilatation, structure disturbance of both kidneys, appearance of multiple strong echo. The child was clinically highly suspected of polycystic kidney disease. Targeted sequencing showed two mutations in exon 32 and exon 50 of PKHD1 gene, respectively, c.4274T > G, leading to p.Leu1425Arg, c.7973T > A, leading to p.Leu2658Ter. Verified by PCR, the father has one mutation of c.4274T > G. CONCLUSION The clinical manifestations of autosomal recessive polycystic kidney disease are multiple renal cyst, cyst of liver and liver fibrosis, intrahepatic bile duct dilatation. Two mutations (c.4274T > G, c.7973T > A) in PKHD1 gene may be pathogenic.
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Genetic testing for retinal dystrophies and dysfunctions: benefits, dilemmas and solutions.
Koenekoop, RK, Lopez, I, den Hollander, AI, Allikmets, R, Cremers, FP
Clinical & experimental ophthalmology. 2007;(5):473-85
Abstract
Human retinal dystrophies have unparalleled genetic and clinical diversity and are currently linked to more than 185 genetic loci. Genotyping is a crucial exercise, as human gene-specific clinical trials to study photoreceptor rescue are on their way. Testing confirms the diagnosis at the molecular level and allows for a more precise prognosis of the possible future clinical evolution. As treatments are gene-specific and the 'window of opportunity' is time-sensitive; accurate, rapid and cost-effective genetic testing will play an ever-increasing crucial role. The gold standard is sequencing but is fraught with excessive costs, time, manpower issues and finding non-pathogenic variants. Therefore, no centre offers testing of all currently 132 known genes. Several new micro-array technologies have emerged recently, that offer rapid, cost-effective and accurate genotyping. The new disease chips from Asper Ophthalmics (for Stargardt dystrophy, Leber congenital amaurosis [LCA], Usher syndromes and retinitis pigmentosa) offer an excellent first pass opportunity. All known mutations are placed on the chip and in 4 h a patient's DNA is screened. Identification rates (identifying at least one disease-associated mutation) are currently approximately 70% (Stargardt), approximately 60-70% (LCA) and approximately 45% (Usher syndrome subtype 1). This may be combined with genotype-phenotype correlations that suggest the causal gene from the clinical appearance (e.g. preserved para-arteriolar retinal pigment epithelium suggests the involvement of the CRB1 gene in LCA). As approximately 50% of the retinal dystrophy genes still await discovery, these technologies will improve dramatically as additional novel mutations are added. Genetic testing will then become standard practice to complement the ophthalmic evaluation.
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Primary pulmonary hypertension after amfepramone (diethylpropion) with BMPR2 mutation.
Abramowicz, MJ, Van Haecke, P, Demedts, M, Delcroix, M
The European respiratory journal. 2003;(3):560-2
Abstract
Primary pulmonary hypertension (PPH) is characterised by sustained elevations of pulmonary arterial pressure without a demonstrable cause, leading to right ventricular failure and death. Hereditary mutations in the bone morphogenetic protein receptor type II (BMPR2) gene result in familial PPH transmitted as an autosomal dominant trait, albeit with low penetrance. The causes in cases without a BMPR2 mutation are unknown, but a syndrome of pulmonary arterial hypertension (PAH) similar to hereditary PPH is associated with systemic connective tissue disease, congenital heart disease, portal hypertension, and human immunodeficiency virus infection, or with the use of appetite-suppressant drugs. The authors identified a BMPR2 gene mutation in a 27-yr-old female who developed PAH after a short course of the appetite-suppressant drug amfepramone (diethylpropion). This allowed molecular genetic counselling and prevention of potentially harmful drug exposure in the patient's son treated for attention deficit disorder with methylphenidate, an amphetamine-related drug. No BMPR2 mutation was found in four additional, unrelated patients with appetite suppressant-related PPH. The findings provide strong evidence that amfepramone can trigger primary pulmonary hypertension in a bone morphogenetic protein receptor type II gene mutation carrier, and indicate that other genes are probably implicated in genetic susceptibility to appetite suppressants.